1. Field of the Invention
The present invention relates to a semiconductor device, in particular, a semiconductor device including semiconductor chips each having a chip size package (CSP) structure, a method for manufacturing the same, and an electric equipment system using the same.
2. Description of Related Art
In recent years, for example, along with an increasing demand for smaller electronic equipment, semiconductor devices strongly are required to be smaller and have higher density (higher integration). In order to satisfy this demand, in conventional semiconductor devices, as described in, for example, JP H11-74407A, the use of semiconductor chips each configured in a CSP structure is proposed.
Referring now to FIG. 9, a conventional semiconductor device will be described in detail.
FIG. 9A is a perspective view of a conventional semiconductor device. FIG. 9B is a plan view of the conventional semiconductor device of FIG. 9A as viewed in the direction of the arrow IXb. FIG. 9C is a side view of the conventional semiconductor device.
As shown in FIG. 9, a conventional semiconductor device includes a semiconductor chip 111 in which two functional circuit blocks 101 and 102 are formed. In this conventional semiconductor device, a plurality of solder balls 141 serving as external connection terminals for external connection are formed on one surface of the semiconductor chip 111 so that the solder balls 141 are electrically connected to a mounting board of a set product in which the semiconductor device is mounted. The semiconductor chip 111 is configured in a CSP structure, so the semiconductor chip 111 is packaged except the solder balls 141. This conventional semiconductor device, unlike ordinary semiconductor devices having pins (lead frame) as external connection terminals, has been considered capable of being miniaturized even when the number of external connection terminals is increased to achieve higher density.
However, in the above conventional semiconductor device, problems often arise when attempting to achieve multi-functionality in that the mounting area increases significantly and considerable time and effort are required for the mounting operation.
More specifically, in the conventional semiconductor device, when the number of various different functional circuit blocks integrated in a single semiconductor chip (i.e., the installed number) is increased, mutual interference is likely to occur between the functional circuit blocks. In other words, when attempting to achieve multi-functionality in the conventional semiconductor device, degradation of isolation characteristics, the resulting degradation of electrical characteristics and the like are likely to occur, and the installed number of semiconductor chips mounted in the set product needs to be increased. Consequently, it has been difficult to suppress the increase of mounting area in the conventional semiconductor device.
Further, when the semiconductor chip is mounted onto the mounting board of the set product, the semiconductor chip usually is disposed on the mounting board, being held by the arms of a mounting device or the like. For this reason, in the conventional semiconductor device, it is necessary to ensure, in the mounting board, in addition to the mounting area in which a plurality of semiconductor chips are mounted, a space for disposing the semiconductor chips on the mounting board for each of the plurality of semiconductor chips. Accordingly, when attempting to achieve multi-functionality in the conventional semiconductor device, not only does the actual mounting area increase significantly, but also considerable time and effort are required for the mounting operation.